Why is that bad news for the league? If people will pay more to see your product, that's a good thing for the league. Having both attendance and ticket prices go up means that there's still untapped demand out there - check the ol' supply and demand curve. That's a plus.

It's bad news because it limits the fan base to only those who can afford to go, which is usually not a casual type of fan. Someone who doesn't watch a great deal of hockey is less inclined to buy a $75+ seat when they can spend 1/3 of that or less at another event and get as much enjoyment out of it.